The cat’s purr is universally recognized and widely enjoyed, even by people who may not care that much for cats themselves. The other common cat vocalizations are also well known, and some of them have entered our language, such as “caterwauling”, which is widely used to describe human singing that the hearer does not like.
The Many Sounds Cats Make
Cats have the widest range of vocal production of any of the usual pet animals, except for birds. Some studies indicate that cats also have substantial ability to understand human communication, and much has been written by professionals in this field. The sounds that cats make serve largely to communicate emotional state and information that has emotional significance, while they are often instinctively able to understand the emotional correlates of things that are said to them by humans.
How Cats Purr
The great variety of cat vocalizations is due in part to their well-developed vocal tract and in part to their advanced brain. In particular, nerve cells in the purring center in the hypothalamus, a part of the brain just above the pituitary gland, are capable of very fast and rhythmic firing, that causes rapid changes in the configuration of the cat’s vocal cords, which impart vibration to the air moving past as the cat exhales and inhales; this results in the generally soothing sound known as purring.
This motoring sound generally means contentment and conveys the message that the cat has no plans for aggression; it also serves as communication between the mother cat and her newborn offspring so that they can find her to feed, and is thought also to communicate the desire for food to humans in the domestic situation.
However, unknown to most people outside the animal professions, purring can also accompany fear and pain, and seems in these circumstances to produce endorphins, the natural opiate compounds that in cats and humans can block pain and elevate mood.
The meow has its origin in the vocalizations of kittens to their mothers when in need of assistance, but in the wild it fades away as the maturing cat does not need its parent. Thereafter, the meow is almost exclusively used by domestic cats to communicate with humans, who usually assume the role of parents for domesticated animals. The meow is usually a request for food, attention or admission to a house or a room, but it can also represent a greeting, particularly when the human is returning home.
A shorter and often interrogatory “mew” often signifies hunger or loneliness in younger cats, while a more frequent “meow” by an older cat may indicate difficulty seeing, hearing or getting around. Longer and more plaintive meowing of a more throaty quality may indicate irritation, worry or displeasure with a situation, while repeated meowing of this kind can be a sign of illness or injury.
More positive are the short birdlike sounds known as chirps or trills, which are first used by mothers to get the kittens to follow her. The chirps come to be used by kittens and grown cats to get human attention or to direct human attention to something. They are also signs of happiness and excitement, and can be a particularly affectionate greeting.
Cats will often chatter with their teeth at birds, squirrels and other potential prey, particularly if the prey is outside or otherwise inaccessible. Indoor cats may also respond this way to videos or animal television provided for their amusement, and may chirp or squeak if particularly excited. This is a predatory behavior, accompanied by stress or frustration at being unable to satisfy predatory instincts. The chattering sometimes resembles the sounds made by rodents or birds, and has been suggested to be a hunting call involving mimicry. On the other hand, cat hunting usually involves silence and stealth rather than attracting the attention of the prey.
These are positive vocalizations that are usually pleasant for humans; caterwauling is positive in that it is intended to encourage mating, but this plaintive cry or moan by a female in heat who is seeking a mate may not be soothing to people. The caterwaul is an abbreviated form of a yowl, which is cat-to-cat communication signifying availability for mating and the urge to do so, and can also be used to proclaim a territory or to communicate worry or discomfort. Illness, cognitive decline and less acute sensory function can also result in yowling in older cats. Cats of all ages may yowl when they are unhappy, lonely or bored, and yowling is a signal by strays and feral cats that they wish to take over a territory from its occupant.
Caterwauling by an accessible fertile female will attract a male, often with attendant yowling. This will lead to mating, which is painful for the female because of an initial neck bite and later application of the barbed male penis and will usually result in a scream. Screaming is also a feature of fighting, and is preceded by yowls of increasing length and intensity, and usually attended by biting and paw swiping. Such fighting is more common and more intense among cats who have not been spayed or neutered, but fixed indoor cats can also be involved in such altercations and are at risk for injury.
The hiss is a warning that a cat feels threatened and is prepared to fight if needed. Hissing is usually accompanied by the behavioral features of impending rage: back arching, hair puffing, ear flattening, tail twitching, spitting and opening of the mouth to reveal the teeth. This may happen often and with minimal cause in irascible cats as well as feral or stray animals or those who have been abused, or may be infrequent in friendly and outgoing cats. Some cats that do not hiss may growl or snarl to express anger or fear or to respond to a perceived or actual territorial threat. Growling or snarling accompanied by back arching and tail twitching is a signal to back off that is equivalent to a hiss.
Over time, listening to these vocalizations and observing the behaviors that accompany them will allow cat parents and friends to understand the cat emotional and feeling states that they express. We are just beginning to understand the ways in which cats think and express themselves, but we have enough knowledge now to be able to at least start to understand these somewhat mysterious companions.